


ambitious

by victorlimadelta



Category: Voltron: Legendary Defender
Genre: Anal Sex, Derogatory Language, Dildos, M/M, Oral Sex, Plot What Plot/Porn Without Plot, Power Bottom Keith (Voltron), Praise Kink, Service Top Shiro (Voltron), Sex Toys, Size Queen Keith (Voltron), Trans Shiro (Voltron)
Language: English
Status: Completed
Published: 2021-03-01
Updated: 2021-03-01
Packaged: 2021-03-13 07:54:25
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 5,651
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29773002
Author URL: https://archiveofourown.org/users/victorlimadelta/pseuds/victorlimadelta
Summary: “Nope,” Keith says, popping thepso hard that an extra bubble of spit dribbles off his lips. He is utterly un-self-conscious as his tongue darts out to lick up his mess. “I’m gonna fuckmyself.”“Ambitious,” Shiro says. “I like it.”—Keith is a size king. Good thing Shiro has interchangeable prosthetics for more than his arm.
Relationships: Keith/Shiro (Voltron)
Comments: 1
Kudos: 55





	ambitious

**Author's Note:**

> AMAB language used throughout.

This is the best place in the world, Shiro thinks. He’s in bed with Keith, comforter tangled around their legs as Keith vaults into his lap. The good-morning kiss from his partner blooms over Shiro’s face like a sunrise, then goes blood-red and hot around the edges when Keith presses forward to deepen it. “Hello to you too,” Shiro murmurs into his mouth, pushing the words in with a slide of his tongue.

“Hey,” Keith says back, biting playfully at the swell of Shiro’s bottom lip. He even has the audacity to look a little shy about it, even with the long, lean line of his body draped against Shiro’s like he could phase through his skin like this. There’s something hungry about his hands, the way the fingertips dig into the cut muscle of Shiro’s front, outlining hard-won, scarred pecs, the old claw marks gouging his obliques, the thick trail of white hair under his navel. “Missed you.”

“How long was I asleep?” The turn of Shiro’s smile quirks into their kisses, traced by the point of Keith’s tongue.

“Not the point,” Keith quickly counters, and. Ah. Slung across Shiro’s thigh like he is, the soft cotton of his boxer-briefs brushes between the two of them, outlining the morning wood that’s bumping into Shiro’s hip.

“Needy,” Shiro teases, kissing him deeper. Keith goes shiver-slack in his arms and opens his mouth, pliant and suggestible.

It’s a special kind of indulgence, for the two of them. These weekends together are truly a string of stolen moments, accrued PTO begrudgingly given by the Galaxy Garrison and spent on the kind of shore leave that doesn’t take Keith too far from the nearest Blade of Marmora base in case of humanitarian-adjacent emergency. Shiro even has a special captain’s shuttle set aside for these voyages, personalized tip to tail, everything from disengaging the frumpy autopilot that only uses sixty percent of her potential to the sticky glow-in-the-dark stars on the ceiling of the bed berth.

Keith doesn’t seem too keen on wasting any time, though. Their _rends-tu_ last night was unforgivably quick, burning off just enough of their energy to settle down and sleep—clearly not enough for either of them. “Need you,” Keith whispers, lips finally slipping away from Shiro’s.

He’s very good at saying what he means, even when he’s not talking. His mouth falls in precision meteor strikes, one impact after the other, across Shiro’s jawline and down the lay of his throat, sparking stars alight under his skin. As he sinks down Shiro’s front, his hard-on brushes Shiro’s thigh; to tease, he raises his knee, and Keith instinctively ruts against it for a glorious half-second. “How?” Shiro asks.

“Need you in me,” Keith answers, mouth on the muscles of his chest.

Oh, he’s in _that_ kind of mood. “Yeah,” Shiro says breathlessly, “yeah, we can do that,” which abruptly gets cut off in a strangled sound that has him clapping his hand over his mouth to stifle it—Keith darted his tongue to a nipple to put it between his teeth, so forcefully that Shiro can still feel it through all the scar tissue.

It’s only a little bit of a logistics issue by now, not the massive one it used to be. His shuttle, his rules, and these technically wouldn’t count as contraband anyway seeing as they’re classed under ‘gender-affirming prostheses.’ Never mind that he has multiples, or that some definitely aren’t human. His weekends-in-bed briefs have a helpful O-ring in the front that easily accommodates a flared base, so it’s just a matter of choosing which one.

Shiro leans over to reach under the bed for the compartment nicknamed the Dildo Drawer and surveys his options. The assortment that stares back would be overwhelming if the collection hadn’t been lovingly curated over the years. Hovering his hands over a few, he gets a little distracted by the heat of Keith’s body hovering down, down further still. A tender kiss to the scar under his nipple, some naughtier ones trailing down his side. “Got a preference?”

“Whatever you want, big guy.” Keith’s eyes are stellar when he looks up at Shiro like this, all guile and yet no pretension with his hands covetous on Shiro’s abs. At some point, when Shiro was preoccupied with their glut of choices, Keith kicked off his boxers; he’s naked now, nothing but skin and heat wherever their bodies touch.

Yeah, Shiro doesn’t want to dither around anymore. What he ends up grabbing is almost offensively normal: a putty-colored, tacky-feeling dong, barely any flare to the head, a reasonable six inches, thick enough for good penetration without a struggle. He grabs lube while he’s rummaging around in here, no sense in not being prepared, but, uh. Maybe they won’t need it? Because as soon as he puts the sex toy in position, Keith is there, licking the silicone from base to tip before he opens his jaw to take him in.

He can’t feel Keith’s mouth on him. Not physically, not like this. But there’s still the devotion and desire in his hooded eyes, the pornographic clasp of plush lips around the prosthetic, the hint of a flush starting high on his cheeks just where his long hair brushes his cheekbones, and Shiro gets that same chill up his spine anyway. “Yeah,” he whispers, curling fingers around Keith’s ear to trace the bobbing movements of his head. “Just like that, hotshot, you’re doing so well. Such a pretty cocksucker for me.”

Keith moans, eyes sliding shut, and takes the dildo so deep into his mouth that Shiro gets the reverb of the little ‘nnk’ soft palate choke on his fingertips. It grinds the suction base against his mons, just barely getting good pressure on the base of his dick, but Shiro probably can’t handle much more than that at the moment—not with Keith’s throat clicking as he works, ass in the air as he sucks and slurps.

He’s _presenting_ , isn’t he, the catty little thing. Shiro’s other prosthetic—the metal one, the one permanently grafted to him—smooths down Keith’s spine, tracing gentle fingertips down each vertebra until his back is arched delicate and flexible, sacrospinalis anchoring his core. When he pauses at the cup of his lower back, Keith tilts his hips in invitation, showing off the perfect bubbles of his cheeks, goading Shiro into taking what he wants.

Keith’s pace doesn’t even hiccup as Shiro walks his fingers down his sacrum, crawling closer to his prize. His chest does, though, when that possessive touch finds the dip of his hole, breath going backwards for a fraction of a second before he works through the stutter and spreads his knees on the mattress. “Good boy,” Shiro rewards him, rubbing along the cleft of his ass.

He’s soft here, forgiving. It surprises Shiro a little—they didn’t get around to assplay last night, so there’s no reason for Keith to be so ready. Unless, Shiro’s horny brain supplies helpfully, Keith fucks himself on the regular when they’re long distance. On his fingers. With a vibrator. Sitting on disembodied dick, wishing it was attached to his man. And isn’t the concept of that just a little intoxicating? That Shiro can consume his thoughts so thoroughly, even galaxies away.

Keith even seems to surprise himself when Shiro sets a fingertip against the furl of him and starts sinking in easily as Keith gives to just that tiny bit of pressure. No reflexive clench, just a knuckle already circling around the inside of that relaxed rim. Keith keens around a mouthful of synthetic cock, and Shiro chuckles. “Slut,” he praises him, adding a second and spreading his fingers to test the tension of his hole. “You don’t even need lube, do you, baby? Just want to drool on my cock until it’s wet enough for me to fuck you.”

There’s a little sound stuck in Keith’s mouth at that, a whiny sort of _huh-uh_ caught behind his teeth. When he pops off, an obscene string of spittle still connects his flushed, glossy lips to the tip of Shiro’s toy. “Nope,” he says, popping the _p_ so hard that an extra bubble of spit dribbles off his lips. He is utterly un-self-conscious as his tongue darts out to lick up his mess. “I’m gonna fuck _myself_.”

“Ambitious,” Shiro says. “I like it.” He likes it even more as Keith climbs up the bed and throws a leg over his waist to straddle him properly. But then—then he’s already taking the prosthetic in hand, holding it in place as his other hand splays on Shiro’s crunching abs to keep himself steady. Shiro panics. “Keith, I barely even—and you didn’t use—don’t—”

“Relax,” Keith tells him, and follows his own advice, his body going slack as he sinks down.

“Oh,” Shiro breathes out, hands coming up to scrabble at the muscle of Keith’s thighs. “ _Oh_ ,” heavy with meaning, like he can actually feel the clench as Keith opens. “Ohh,” drawn out in a wondrous sigh, because that’s nothing but spitshine and determination, and the harsh pull of Keith’s lower lip between his own teeth as his thighs go tense about halfway to bottom. “You like it like that?”

“Yeah.” A little nod. Rolling his hips a little, and from this angle Shiro can see where the dildo disappears into him. Of course he does, Shiro thinks, a little delirious, likes it fast and rough and reckless. “Like how it burns.”

“Always my little spitfire,” Shiro says, and Keith laughs, his stomach pulling in—a sound that twists into a moan, and Shiro wishes he could actually feel the flutter of his rim as it twitches with the chuckle. “Doesn’t hurt?”

“Never.” And then—then Keith’s flush with him, sitting on his lap, cock hard and heavy and red with the barest drip of precum at the tip, counterbalanced between a hand on Shiro’s side and a hand spread across the top of one of his massive thighs. He starts to rise up just that little bit, balls dragging against the cloth of Shiro’s briefs as he works his hips in a tight circle.

Fuck, he’s got to know how good he looks when he does that. “You’re gorgeous,” falls out of Shiro’s mouth, hands petting along Keith’s flanks over and over as he starts to ride in earnest. “So good at this.”

“Yeah?” Keith has enough of a fight left in him that he quirks a brow down at Shiro, half-smile showing off a glint of Galra fang as he moves. There’s a soft little wet sound with every thrust, a rhythm of _pat pat pat_ like music to Shiro’s ears “Like watching me fuck myself on your cock?”

Shiro nods, destroyed. His hands grip, hard, just above Keith’s knees. It’s all he can do, just see, can’t feel, but—it makes his spine go all liquid hot, knowing this is how it would be if this—if that was really— “Good size?” he asks.

Keith huffs out through his nose and ups the pace. His eyes are black with challenge. “Could be bigger.”

“Oh?” Shiro questions him, and gets a wicked grin in return. “Oh, you want more already?” And he may be many things, might be the former Black Paladin of Voltron, current Captain of the IGF-Atlas, head of an elite squadron of young MFE pilots, the Galaxy Garrison’s golden boy and the Galra Empire’s Champion—but above all else, in this moment, he is a _weak man_ , so senseless for the pretty creature panting and bouncing in his lap. “I’ll give you more,” he promises, and Keith preens.

_More_ is a different toy. A lot more realistic, made to look natural on Shiro’s body down to the skin tone. Keith rears up and Shiro switches out what’s in his O-ring. The synthetic skin of the new one feels much better in his hand, warms nicely with his body heat and slicks well with the lube Shiro’s using. It’s longer, thicker. More proportional, really—he’s a big guy, this is what he’d have, eight inches that he can barely close thumb and forefinger around. The head is ruddy, like it’s really blood-filled, and there’s even an artificial foreskin that he rubs back and forth across the thick ridge of the crown just to tease Keith’s starving black-hole eyes. “Hands off,” he snarls, composure snapped by the gesture, “let me have it,” newly-clawed fist circling round the base.

“Love to see you go feral for it,” Shiro says, helping him line up. And then—Keith’s face twists, a low, purring croon slipping out of his throat as his head hangs between his shoulders, and there’s even a wet little pop as the head breaches him. Shiro’s dick slips in, in, further, further still, until just a few finger-breadths remain at the bottom. Keith tenses there, and Shiro splays his left hand along his lower back, massaging in a little warmth to ease the undeniable strain. “Too much?”

“Not enough,” Keith insists, and practically throws his ass down to take those last two inches.

With the weight of his whole body slammed into Shiro like this, the broader flare of this prosthetic grinds _right_ against the start of the real thing through the fabric of his briefs. The incandescent flash of pressure shocks an indecent noise out of Shiro’s throat, one that he has to swallow right back down when Keith does it again. _Again_ , working up to a slow rhythm that has Shiro’s nails curling into his skin and raking across his back, his metal arm bruising perfect fingerprints into his thigh. “Just—nnh—just like that, sweetheart,” Shiro encourages him, lifting his hips in counterpoint.

The glare he gets from Keith would be cute if it wasn’t so threatening. “Don’t move,” he grits out, pinning Shiro to the mattress with the raw power in his thighs.

“So I’m just supposed to—” and his breath goes backwards with the filthy movement of Keith’s hips that fucks the dildo deep into his guts, ruts it hard against Shiro’s cock. “To lie here and look pretty while you get yourself off?”

“You always look pretty,” Keith pants out, too focused on fucking himself to remember to be self-conscious of his bone-deep love for Shiro, and Shiro’s heart sings. “Let me do all the work, starlight.”

The nickname hits Shiro in a tender place right above his solar plexus, making him smile up at his partner. “What about hands?” he asks, flexing his fingers against Keith’s skin. “Does that count as _don’t move_?”

“It does not,” Keith allows him. “Yet,” with a knife-sharp, or-else edge to the consonant.

“Good,” Shiro says. His left hand sweeps down Keith’s back, soothing over fresh scratch marks and petting down his tailbone, before dipping between his pretty cheeks. “Good boy,” he murmurs, tracing out Keith’s rim where he’s being penetrated, the slick give-and-take as he rides. “Good little whore,” he commends him, and Keith’s internal metronome ticks up, pace faster.

It’s not until Shiro gets false fingertips around a pert nipple, though, that Keith lets out a sound, a constrained whimper like the pleasure is too much for his body to hold. When Shiro pinches, Keith lets out a yip of a breath, gasps in hard enough to press his chest against the waiting hand. A twist and he howls, eyes scrunched closed but mouth wet and red and open, punctuated by the marks of his own teeth in his lips. “Shiro!”

“That’s it,” Shiro soothes him, thumb rubbing over the abused flesh. The slapping sound between their bodies is getting louder, Keith working himself up with tension coiling in his thighs. Shiro switches to the other side of his chest, cupping firm muscle in his palm before pinching here, too.

Another animalistic noise rips out of Keith. “If you do that again I’m gonna come,” he threatens, bouncing with abandon now.

“Then come,” Shiro tells him, like it’s that simple. He nudges a fingertip against his rim like he might breach, twists his nipple. “Come for me, Keith. Come on my cock.”

Keith holds out for ten seconds. Ten glorious seconds where he’s hilted on Shiro, looking down at him wild-eyed, hips rolling, a hand of his own pinching his free nipple like it’ll stave off his impending doom. But he follows direction so well, listens with his body even when his mind is half-offline, and without Shiro even touching him there, his dick starts twitching. He’s beautiful in the throes of orgasm: eyes hazy in concentration, mouth relaxed and drooling, back bowed and thighs lax. Even his cum is pretty, spurts arcing artistically over Shiro’s stomach and icing over his scars, the grooves of his muscles. “Fuck,” Keith sighs. “ _Fuck_.”

“That was the idea.” Mmh, the way Keith’s gone all relaxed has him crushed against Shiro’s pelvis, and the sensation on his dick is just this side of unbearable. God, he needs touched. “How was it, baby?”

Keith’s still catching his breath. Sex-sweat streaks his hair in inky swirls across his forehead, wisps curling around his throat. His adam’s apple bobs heavy with a swallow. “Shiro,” he rasps, a blade against a whetstone.

Shiro rubs his arm, a calming gesture. “Yeah, sweetheart?”

“What made you think I was done with you?”

Shiro gulps.

On shaking legs, Keith rears up from where he was sitting on his dick. It falls out of him with a noticeable slurp that has Shiro’s face coloring, the blush tightening around the edges of his scar and making it feel like his face is falling apart. “I want the black one,” Keith decides.

“The black one?” Shiro’s fingers grip on Keith’s upper arm, firmer than he intended. “Keith, it’s—”

“I know.” Keith places his palm, gentle, along the dip between Shiro’s collarbones. Then the sweeping beat of his hand moves up. Up, and up, pressing in subtly on his throat before grasping at his chin to make Shiro look him in the eye. His sclera are yellow, pupils fat black slits. “I want it.”

Shiro cannot scramble for the thing fast enough. Toy #3 is even bigger than the last, a broad base and hefty body for Shiro’s pleasure, eleven usable inches with girth Shiro can’t fully close his fingers around for Keith’s. His partner meets him halfway, snapping the used dildo out of the O-ring and holding the rubber open so this one will fit. Technically it’s one-size-fits-all-dongs, but Keith seems intent on stretching the limits this morning in every way possible.

They fit this one snug in the holster, but before Keith can mount him again, Shiro passes him the bottle of lube. Keith gets the hint, pouring a handful and slicking the shaft inch by inch. Meanwhile, Shiro has wet fingers between his legs, Keith’s balls pillowed on the pulse point of his wrist before he finds the barely-there gape (!) of his hole. Three broad fingers, tucked in to the knuckles of his hand, have Keith hugging around him, clingy and blood-hot to the touch. “Mmm,” Keith hums in appreciation, squeezing around Shiro.

A fourth finger might at least approximate the width of this new cock, but folding his little finger in is a struggle for Shiro. “You gonna be able to take it?”

Wrong question, apparently, because Keith puts a hand on his chest to flatten him to the mattress. “Shut up and trust me,” he growls.

Shiro grins, bright and aroused. Confident Keith is his favorite Keith. “I do,” he reassures him. “I always have.”

“Sap,” Keith says, a soft hiss, and swats at Shiro’s intrusive hand.

They come to a compromise, Shiro hooking a thumb inside him to keep him open while Keith holds the black silicone steady. Slippery like this, the blunt head skips across his entrance once or twice, and then—then it catches, and both of them gasp as Keith blooms open around it. The sweet little moue of his reddened lips twists as he lets gravity do the work. And maybe Shiro can’t actually help with much, but what he _can_ do is hold Keith’s ass, one perfect pert glute in each of his large hands, and hold him apart as this thing sinks into him.

Keith’s breathing hard, chest heaving all the way down to his stomach; there’s a concentration line between his eyebrows, his long eyelashes fluttering over flushed cheeks. The sound of devastated pleasure that rips out of him when the girth fucks into his prostate reverberates in Shiro’s teeth, and still he’s taking it in. Halfway down and he starts playing dirty games with his hips, cantilevering the toy in the holster and rocking pressure back and forth across Shiro’s cock still in his briefs. “Yes,” he moans, “c’mon, more,” like he’s trying to bully his body into behaving.

Shiro knows well enough not to move his hips by now. He might have the starring role, but this is undoubtedly Keith’s show. “Easy, baby,” he says, and brings both hands to his hips to put some weight on him, guide him down.

“That’s it,” he says, “no hands,” and Shiro might almost feel guilty that he lost the privilege were it not for Keith actually closing his fingers around his wrists to pin his arms down at his sides. “I told you,” he says, a little out of breath, “I’m gonna do it, let me do it.” And maybe it’s his stubbornness or maybe it’s something in his Galra side, showing more and more the longer they fuck, but he punches through whatever was holding him up with a shout of victory, head thrown back and all his fangs showing as he wriggles all the way down.

“Holy shit,” Shiro breathes. Like this, he could swear he can feel the entire weight of Keith’s body between his own legs, urgent against the swell of his dick. “You—you—“

“Yeah,” Keith says, and swivels just that tiniest bit. Shiro’s eyes roll back, because he—“can you feel that?” Keith’s asking him through the bloodrush in his own ears. “Can you feel me?”

“Yes,” Shiro hisses, head falling back into the pillows. His helpless hands need something to hold onto or he’s going to fall apart; Keith doesn’t chastise him when he holds his calves. The tension here is incredible, every muscle from his core to his legs working his body up and down, wrecking himself more and more.

And it’s not enough just to take him, no. Never would have been. Keith _rides him like he stole him_ , the grown version of the delinquent he first met so long ago. Shiro’s eyes trace a drop of sweat as it falls from Keith’s chin, slides down his chest close to one of his abused nipples. Caresses every dip and curve of his lean abdomen, just barely bypassing his navel trail and hugging his adonis line before finding the base of his cock. Hard again, bobbing obscenely with every drag and draw of Keith’s body. “You feel so good,” he’s muttering, almost lost in the drumming of their heartbeats. “So good, Shiro, I want more, I always want more, want you spread out under me like this so badly I can barely breathe—”

“Yeah,” Shiro says, “oh, Keith,” because it’s more than the sex, it’s always been more, almost too much for either of them to carry alone. “Wish we could—wish I could keep you like this, aching and desperate, I always want you so badly when you’re away and we can’t ever make up for lost time like this but fuck do I try—”

“I know,” Keith’s soft words at odds with the harsh, greedy movements of his body, “Shiro, fuck, I know, oh, it’s always, hhh—more, I want, I want,” and he’s dissolving into incoherency the longer he fucks himself.

“Gonna come again?” Because if he keeps moving the prosthetic like this, Shiro might actually be able to make it happen with him. Keith shakes his head, though. He opens his mouth to speak, but the only word Shiro recognizes is ‘Galra.’ “What is it, baby?”

Keith tries again, spitting English past his mouthful of fangs. “I wanna come on the Galra one,” and he _pouts_ in frustration at having to voice his desires. “Gimme the Galra one.”

“I think—” and then Keith knocks the words out of him, too— “I think that thing is classified as a weapon in three different star systems.”

“I don’t care!” Keith’s skin is getting that bruised purple tinge the longer he makes himself hold out. “Give it to me, Shiro, or I swear I’ll—”

“Okay, okay,” Shiro soothes him over, petting at his leg hair. “If you think you can take it, I’ll give it to you. Greedy baby.”

The insult looks like it hits Keith right in the gut, stomach hollowing as he keeps riding the black one. Even as Shiro fumbles it out of the harness, it stays in Keith, who’s panting as it’s lodged in him to the base. “Hurry,” he slurs.

“I got you, baby, don’t worry.” The problem, though, is that the Galra one is _massive_. Just—obscenely, offensively large. It’s difficult to wrestle it into the O-ring with Shiro’s lube-tacky fingers, and then it’s so heavy that it starts to fall forward once he finally counterbalances it on his crotch. The elongated shape of the base means that it curves nicely over both inches of Shiro’s cock. It’s a pretty, pearlescent lavender color, all fourteen inches of it, with a paired series of bumps on the underside and three head-like ridges near the tip. At the base is a larger sort of bulge, one that Shiro doesn’t like thinking about too hard or it makes his insides cramp in reflexive pity. “C’mere,” he urges Keith closer, “back on me,” as he drizzles the entire rest of the lube bottle on the thing in a useless gesture to make it seem any less intimidating.

Keith’s eyes on it are black and reflective, entire galaxies to themselves. He’s still fucking himself with the black toy as he crawls back into Shiro’s lap—with two more fingers tucked in alongside it to pull himself open enough to be able to take this thing that’s now attached to Shiro. “Fuck,” he breathes, reduced to nothing but swears, and perches himself up on shaking thighs.

Shiro reaches behind, closes his hand around Keith’s at the toy’s base, and urges it out. Keith tips forward, putting his hands on Shiro’s chest for balance, and as the black dildo falls out of him, he’s rucking forward, tucking the head of the Galra one inside himself. It’s Shiro’s turn to curse, a drawn-out “shit!” as Keith holds himself up. God, this dildo must be half the size of his thigh around and nearly as long, and he’s really going to take it?

Yeah. “Yeah,” Keith sighs, tense and tight, but he’s still—he’s doing it, and Shiro watches, mesmerized, as his body gives way. There’s a stressed little snap with each ridge that breaches him. “Oh, fuck. Oh, Shiro—fuck, you gotta feel—” and he scrabbles with his fingers until he finds Shiro’s hands, brings them up to drape them around his waist.

Shiro’s palms fit perfectly into the narrow tuck, thumbs reaching for his navel, fingers splayed along the sensitive, hot skin of Keith’s lower back. And, as Keith continues to sink down, he—he feels—“oh,” he realizes, that’s. It’s big. It’s _so big_. “Is that—”

“That’s you,” Keith says, dropping his weight into Shiro’s grip. “Fuck—you feel so—”

“Wanted to feel me like this, huh?” Shiro rubs his thumbs against Keith’s stomach. The more he takes, the more it bloats. That’s an actual honest-to-God bulge under his skin. “So big you feel like you’re choking on it,” and Keith, obligingly, chokes on his next moan. “So thick you wonder how you could ever feel full with anything else, ever again.” Keith nods, taking another inch and screaming as one of those ridges strokes his prostate. A blurt of precum drips onto Shiro’s stomach. “I know you just wanna be fucked like this, all the time.”

“All the time,” Keith thoughtlessly repeats, dick drooling again as he takes even more.

“Good boy,” Shiro tells him, still pulling Keith down. I’m so lucky, he thinks. “You’re so lucky,” he says instead, voice straining—the base of this cock is _torturing_ him. “To have a man who can satisfy you no matter what—no matter how much of a glutton you are, or how much you want, your man can give it to you.”

“‘M ruined,” Keith agrees. “Ruined for anyone else—Shiro—”

“Want you to feel this,” he says, out of his mind with the way Keith’s rocking rolls pressure across his own dick, “wanna get so deep in you you won’t be able to get me out of your mind for days, want you to remember who loves you, baby.”

Keith’s moaning with every breath, now, hitching in little circles around the part of the dildo he can actually take. “Shiro,” he says again, “Shiro,” like his name is the last thing that makes sense in his fuckdrunk mind, “Shiro,” pushing his left hand down off his side, rolling his hips up and closing Shiro’s fist around his dick, “please, I need—”

Shiro knows what he needs. Fuck, he needs the same thing, he’s been teetering too close to the edge for too long. He jerks his partner off, fast and hot, a twist just under the head with every stroke. “Come on, sweetheart, show me.”

And he does, perfect little thing, spills over Shiro’s fingers and onto his abs again, screaming his pleasure so it reverberates from the hull of Shiro’s shuttle. He orgasms so hard there’s a twitch all through his body, rippling the muscles under Shiro’s prosthetic hand still on his side, and that just makes him even louder as his insides grip the Galra monstrosity still fucked halfway into him. “Shiro...”

Keith’s legs are shaking. “Come on, now, weight on me, that’s it,” Shiro tells him, and helps Keith pull himself off the toy. There’s a little whimper of aftershock when the ridges stretch his rim again, but then—then he lets go, nearly limp in Shiro’s arms now that he’s empty. The heavy dildo falls to one side, and Shiro chokes on his own tongue as it slides just far enough away that it’s no longer doing him any good. “You okay?”

“Almost.” He’s exhausted, that’s plain to see, clubbed nails and blunt teeth and pale skin and purple irises. But he still brings up a clumsy hand to twang at the elastic of Shiro’s underwear. “Off.”

“What?”

“Did you come?”

Stubborn man. “I can do it myself.”

“I don’t want you to.” And he looks so earnest about it that Shiro doesn’t have the heart to tell him to back off and rest. “Off,” he repeats.

They’re probably useless by now, anyway. There’s a wet peel-away from between his legs as he pulls down his briefs. “You don’t have to.”

“Stop that,” Keith says. “I want you to come in my mouth.” Shiro apparently isn’t going fast enough, because Keith’s numb hands intercept his halfway down his legs, stripping him naked and spreading his knees to let his body fall between his thighs. “That okay with you, _sir_?”

His breath is already humid around Shiro’s exposed cock; it pulses so headily it makes Shiro a little dizzy. “Permission granted,” he says nonsensically.

And then Keith’s mouth, hot and slick, becomes the clarifying point of contact between the two of them. The sly little kiss to the tip sucks it just barely between his lips, and then he’s licking all along it, cupping the jut of it in the soft meat of his tongue for the barest fraction of a second. “You taste,” Keith sighs, “so good,” and shoves further up between Shiro’s legs, holding his strong thighs apart.

“You _feel_ so good,” Shiro tells him, “sucking me off like that—” and then Keith works his jaw open, holding it in his mouth, tucking his tongue against the underside and curling sinful around the stunted shaft. It makes something in Shiro’s core clench, especially as Keith’s cheeks hollow, the sweet suck of his mouth yanking his release closer. “Don’t stop,” he gasps, a shaking hand coming down to pet at Keith’s hair, “fuck, ‘m close—”

Keith pulls away. Because he’s secretly evil and delights in Shiro’s suffering, he’s sure. Instead of his tongue, though, his thumb starts roving between his legs—dipping down far, almost too far, into a slick place Shiro doesn’t want touched, before it comes up to rub at his dick, jerking him off fast and wet. “Come,” Keith purrs, latching on again with that extra pressure.

Shiro hollers, probably. He goes deaf there for a minute, blind even, holding Keith close by the nape of his neck as his orgasm rips through him, throbbing heavy against his tongue before seeping out to his limbs. Keith is so good, with his little kitten-licks from the inside of his mouth spiking Shiro higher, ever higher, until he shatters, hands gone pins-and-needles and toes curled in.

It ends with both of them panting, wet from sweat and lube and other unfortunate fluids. With what must be the last of his strength, Keith pushes up Shiro’s body and kisses him sweet on the mouth. “Good morning,” he says.

Shiro laughs. “Good _night_ ,” he answers. His body feels pleasantly heavy, utterly relaxed, pain-free and swimming in endorphins. Keith tucks his body into Shiro’s side as he starts to drift back under, arm slung over his tacky stomach. Not just the best place in the world, he thinks, laying a kiss in Keith’s messy cowlick. The best place in the universe.

**Author's Note:**

> Happy birthday Shiro! Over 10K works in the otp:true Sheith tag on AO3!


End file.
